The invention relates to a selector lever device especially for the automatic transmission of a motor vehicle.
DE 196 10 766 C2, which is assigned to the assignee of the present invention, discloses a shift selector device for a transmission. The selector and shift device has a selector lever, which is held in a selector lever seat or held by a fork head and is mounted so that it can swivel about a first axis for the actuation of a gear shift lever shaft and about a second axis extending perpendicular to the first axis for performing an actuation movement. The selector lever is further guided in a T-shaped selector gate with two gate branches. At one end of an intermediate branch there is a selector position D, from which the selector lever, guided in the second gate branch perpendicularly to the intermediate selector gate branch, can be swiveled about the second axis into selector position D(+) for shifting up one gear irrespective of the shift program or into a selector position D(xe2x88x92) for shifting down one gear irrespective of the shift program.
In order to achieve an automatic return of the selector lever from its D(+) or D(xe2x88x92) selector positions and to define a home position, the shift and selector device includes a detent unit. At a transition between the selector lever seat and a shift finger formed onto the selector lever seat the detent unit has a retainer, into which a locating ball, supported by roller bearings on a moveable detent element, engages when the selector lever reaches its selector position D. Associated inclined faces, which by the design of their gradient provide for a variable shift force on the selector lever over a shift travel, adjoin the retainer in the direction of each selector position D(+) and D(xe2x88x92) respectively. The moveably supported detent element has a pressure spindle supporting the locating ball, which spindle is displaceable in a cylindrical receiver of the selector lever seat and is supported in relation to the selector lever seat by means of a compression spring.
In either selector position D(+) or D(xe2x88x92) respectively one of two micro-switches is actuated by a shift finger formed onto the selector lever seat. The microswitches are fixed to the base of the shift control housing by means of a holder.
The object of the invention is to provide a selector lever device of the type described above with a particular view to enhanced gear selection and shifting convenience and to facilitate assembly of the arrangement.
In a selector lever device, for an automatic transmission of a motor vehicle, with a selector lever, which is fixed in a selector lever support seat and is guided in a gate structure including at least one gate branch wherein it is held in a home position by a detent unit, the selector lever is supported so that it can be swivelled from the home position about at least one swivel axis for actuating the detent structure providing for an actuation function.
The detent unit has a selector lever seat separate from the first selector lever engagement lever seat, by way of which the detent unit is operatively connected to the selector lever.
Preferably, the detent unit has a selector lever engagement seat separate from the selector lever support seat, by way of which the detent unit is operatively connected to the selector lever. The selector lever engagement seat provides for a positive interlocking connection between the selector lever and the detent device. The separate selector lever engagement seat creates additional degrees of freedom for individual adjustment of the selector lever device, thereby increasing the convenience and facilitating assembly. Furthermore the detent unit can be selectively arranged and adapted to an advantageous alignment of the swivel axis. In this way it is possible, for example, to arrange the swivel axis and the gate branch for the actuation function perpendicular, parallel or in various positions at an angle to a second suitable gate branch.
If the selector lever device has a return unit, which returns the selector lever in the direction of the home position defined by the detent unit by means of a return spring separate from a detent spring of the detent unit, a significant adjustment and return force with a small hysteresis can be achieved. An operator receives clear feedback as to whether a desired swivel movement has been performed and whether the selector lever has already returned to its home position.
The selector lever engagement seat simplifies the detent unit design and/or permits adjustment of the return unit. The detent unit also defines the home position by the and it permits adjustment of the equilibrium position of the return spring of the return unit in relation to one another. This is achieved specifically by a component which forms a detent contour and which is displaceable for adjustment of the home position. A so-called double detent can be avoided and the same force characteristics can be achieved in more than one swiveling direction. The detent unit and the return unit may advantageously be adjusted to one another during or after assembly. In addition, assembly is facilitated.
The return spring of the return unit may act on the selector lever support seat or it may advantageously be incorporated into the detent unit, thereby avoiding the need for tolerances and advantageously matching the return unit and the detent unit to one another, especially if the return spring of the return unit acts directly on the selector lever seat of the detent unit.
In a further embodiment, a sensor unit is incorporated into the detent unit. A deflection from the home position can easily be determined with precision with few intermediate components and without tolerances or play caused thereby. An expensive adjustment process during assembly can be avoided, thereby saving costs. An especially direct detection can be achieved by forming the sensor unit integrally with the second selector lever seat of the detent unit. If a return spring of the return unit and/or a sensor unit is incorporated into the detent unit, a module can moreover be created, which can be advantageously pre-assembled and tested before installation.
Various solutions are feasible, such as sensor units with a Hall sensor, with electrical contacts etc. It is particularly advantageous, however if the sensor unit has at least one photoelectric light barrier, which can detect a certain swivel position of the selector lever. A contact-free, low-wear, temperature-insensitive and accurate sensor unit can be achieved, which is especially suitable for use in a motor vehicle.
In a further embodiment of the invention, the selector lever engagement seat of the detent unit is in the axial direction of the selector lever at a greater distance from the swivel axis than the selector lever support seat, and the selector lever engagement seat is preferably arranged above the selector lever support seat. The frequently unused space above the selector lever support seat is then utilized, and especially advantageous lever ratios can moreover be achieved. The lever ratios mean that the desired high adjustment and return forces of the detent unit and of any selector lever return spring incorporated in the detent unit can be achieved with a lightweight, inexpensive spring element. Furthermore, at a greater distance from the swivel axis any adjustment travel distance of the selector lever is increased. As a result, the larger adjustment travel distance can be detected, in a simple manner, by a sensor unit incorporated in the detent unit.
The selector lever seat of the detent unit can be designed so that it is linearly displaceable or advantageously supported so that it can swivel on one axis. A cost effective, low-friction bearing of simple design can be employed. In addition, the adjustment travels of the selector lever can be translated into relatively large deflection movements, which are easily detectable by a sensor unit and the overall dimensions can be adapted to the prevailing circumstances. It now is possible, for example, to arrange a detent contour of the detent unit in various radial directions emanating from the selector lever.
The selector structure according to the invention can be used in various devices. It can be used to particular advantage, however, in selector arrangements for automatic transmissions, with especially high convenience and ease of assembly requirements.